Hi guys,
I've found a very interesting sound effect on my O2 XDA Mini (=Magician). I've been having the phone for a few days only, but right from the very first calls I noticed that the speaker creates a very high frequency continuous beep-sound, not loud of course, but crazy high, something like the well-known side effect of the old CRT TVs. At first I thought it is produced during a conversation. Then today, I held my phone to my ears without any calls, and guess what: the beep is there. :shock: It's produced always!
I started to look around, and had a hunch that the LCD backlight can be the problem. I played a little with the backlight setting and found that I was right, the sound is poduced only when the light is set to low. It's loudest at the first notch of the light slider, and gets more and more quiet as you set the backlight higher.
Now I wonder if it's a special problem with my phone (like some bad quality filtering somewhere in the power electronics of the backlight system) or if it is the same with your devices.
Please try it and post your comments. Listen closely! And try both ears (not kidding), the sound is very quiet and very high in frequency, so your ears may not be up to the task to pick it.
Have to be honest I can't get a quite second at the moment but I'm pretty sure I've noticed this noise before as well. Another noise which can be irritating is the GSM radio module and it's intermitting buzzing (a quiet version of what you hear when unshielded speakers pick up your signal).
So basically I'm not sure but I think it's a generic issue with the backlight
Hi,
I found that too....
it's quite irritating as it looks like an old TV turned on.
I hope that won't be a problem to our ear in the future
Many guys are looking for a method of recording both sides of voice during a call. But it seems that HTC mobile phones including X1 Xperia don't support internal voice recording. Someone said that's hardware limitation. The only way to recording both sides voice is by turning on speaker.
I got an idea about fix this issue by adding simple circuit to X1 Xperia. Please see the attached file. It's a circuit diagram. As illustrated in the diagram, the signal of other side is introduced by a capacitance. Two voices, one from you, the other from the participant of your call, are mixed together and go to the ADC(analogue/digital converter).
Someone may be concerned about the self-excitation by the feedback. I think the phone works well even if you turn on the speaker, that would introduce the feedback. So the phone will work well if you introduce the signal via electronic form.
I haven't implemented this idea. Guys, please help to review this idea, and make the solution more applicable.
Thanks All!
(Diagram updated, potentiometer added.)
Lol
Maybe implement it and let us know I have a feeling that even with the decoupling capacitor it's still going to cause horrendous feedback. The speaker output will probably still excite the microphone and since the microphone is going to be d.c. shifted into the positive because of the lack of a negative supply. And that's without even knowing for certain the circuitry used here.
It's very interesting idea to make a fix for internal voice recording for X1. Usually speakerphone handsets are factory equipped with some circuitry which avoids unwanted feedback. I doubt that X1 doesn't have one.
You can always experiment with any cheap old phone to check if your idea has a chance to work. Maybe some potentiometer should be used to adjust depth of the feedback.
alias_neo said:
Maybe implement it and let us know I have a feeling that even with the decoupling capacitor it's still going to cause horrendous feedback. The speaker output will probably still excite the microphone and since the microphone is going to be d.c. shifted into the positive because of the lack of a negative supply. And that's without even knowing for certain the circuitry used here.
Click to expand...
Click to collapse
I don't quite understand what you mean. The capacitor between the speakerphone and microphone isn't a decoupling capacitor. It's a coupling capacitor for audio signals. It let audio signals go through and blocks direct current.
And could you explain more about negative supply? As far as I know, symmetrical power supply isn't common in nowadays electric appliance with battery. It seems that self-excitation has nothing to do with negative supply.
Thanks neo and Macko for your reviewing. Experimenting on an old phone is really a good idea! But it is still difficult since we don't know the exact circuitry inside X1.
It's really necessary to have potentiometer to control the amount of signal to be introduced. Thanks Macko!
so phones which cost nearly as much as a laptop cant do smthg that cheap phones can do?
this is a very necessary feature and learning that its hardware limitation is quite disappointing.
what about presenting this idea to htc so they can learn smthg
Nocturnal310 said:
so phones which cost nearly as much as a laptop cant do smthg that cheap phones can do?
this is a very necessary feature and learning that its hardware limitation is quite disappointing.
what about presenting this idea to htc so they can learn smthg
Click to expand...
Click to collapse
X1i is far more expensive than most laptops in discount stores and yes, seems that X1 can't do what SOME of cheaper phones do.
Dear HTC and SE: this is very very ugly dysfunction that XPERIA can't record calls properly! My wife's Nokia E51 does it perfectly. SHAME.
BUT caution please!
I've just done some research and found quite good working software solution of this issue. The problem is that signal from speaker isn't directly provided to DAC, so X1 just records what the mic "hears" from speaker, but if we use headphone or bluetooth headset, then recorded speech volume is far too low. But by applying some dynamics filtering on signal we can achieve desired gain of low volume part.
Here are instructions for volunteers:
- download and install some audio editor, for example CoolEdit
- download your recording from phone, open it in editor; low parts of wave are words of interlocutor
- apply a dynamic filtering as shown below:
- here are the results; as You see, low volume speech is gained by lots of dB, while your speech is almost untouched
My idea is to write some application working in background (as a service) which automatically applies such dynamic filtering DURING recording of a call. This is the best approach, but of course the same results can be reached by postprocessing.
Macko:
How is the voice quality after processing? I think it has some limitations.
sunshaking said:
Macko:
How is the voice quality after processing? I think it has some limitations.
Click to expand...
Click to collapse
Both sides are a bit distorted, which is unavoidable (dynamic processing distorts spectral envelope of signal) but acceptable. Of course all background sounds from opposite side are also gained, so do not talk to somebody who's mowing grass in the backyard
very interesting macko....if u can make such an app for X1..it ll be very useful and popular
Just downloading SDK and getting to work.
makro it is impractical to be forced to process all records. very bad for HTC
sunshaking said:
I don't quite understand what you mean. The capacitor between the speakerphone and microphone isn't a decoupling capacitor. It's a coupling capacitor for audio signals. It let audio signals go through and blocks direct current.
And could you explain more about negative supply? As far as I know, symmetrical power supply isn't common in nowadays electric appliance with battery. It seems that self-excitation has nothing to do with negative supply.
Thanks neo and Macko for your reviewing. Experimenting on an old phone is really a good idea! But it is still difficult since we don't know the exact circuitry inside X1.
It's really necessary to have potentiometer to control the amount of signal to be introduced. Thanks Macko!
Click to expand...
Click to collapse
This is exactly my point. Sorry I wasn't clear. As you say, no negative supply because we are running off of a battery. The signal itself is still an A.C. signal, so, in order to fit it within the confines of our supply it has to be DC shifted into the positive region yes? My point was that this DC level shift will be filtered by the capacitor for the reasons you gave, and so distorting the signal.
http://www.aray.cn/archives/3246
Studying how to disassemble X1.
I've disassambled my X1, but I can't find the microphone.
Here are two photos that might have micrtophone. I guess the microphone is attahed on the right side. But I really can't find it.
Haven't taken my X1 apart yet, but from the outside, the microphone is in the small hole/dent under the "OK" hardware button.
Anyone?
Has anyone found a solution to this hardware problem yet? I've been trying a hundred things with no success.
Can someone with an SPL meter help calibrate the Nexus4 for a sound meter app?
I like Sound Meter Lite but any free app from the Play Store will do.
Thanks in advance!
bump
Anyone? Any recording professionals out here?
This should not take more than 2 min of your time.
- Download a Sound Meter app from the Play Store.
- Play a tone through your speakers. Since phone microphones are mostly flat in the human speech region (300-3k Hz)
it is probably best to use a 1kHz tone.
- Hold an SPL meter aligned with the Nexus4 phone mic (located next to the microUSB port).
Make a note of the dB level on the SPL meter and the app.
- Report the app used and the dB difference between the app and the SPL meter in this thread.
First, are you sure the app is using the mic on the bottom as there is another on the top and it could even be utilizing both and even noise cancellation which would be bad.
Second, the mic on this phone has a very high sensitivity. I would guess the limit would be somewhere around 80db at which point it will start limiting and giving false readings. Pretty useless in and audio environment in that case.
Third, you would want to use pink noise to calibrate a spl meter. A sine wave is generally used to calibrate electrical components of audio (eg. dac).
smacksa said:
First, are you sure the app is using the mic on the bottom as there is another on the top and it could even be utilizing both and even noise cancellation which would be bad.
Second, the mic on this phone has a very high sensitivity. I would guess the limit would be somewhere around 80db at which point it will start limiting and giving false readings. Pretty useless in and audio environment in that case.
Third, you would want to use pink noise to calibrate a spl meter. A sine wave is generally used to calibrate electrical components of audio (eg. dac).
Click to expand...
Click to collapse
1. The Sound Meter Lite app shows a higher dB reading when I point the phone's bottom at the sound source.
Pointing the top (at the same distance) shows a few dB less so I think it's reasonable to assume that the main mic
is indeed at the bottom of the phone.
2. You are right about that. It's a limitation that I'm willing to overlook.
3. Pink noise is ideal.
A tone burst is only useful if one knows the mic's frequency response.
I asked for it because I will attempt to measure the FR on my own and post it here if I succeed.
I will take anything at this point.
HI there guys.
Brand new to this forum.
I've searched for days and I'm unable to find a solution.
I'm experiencing a crackling or a distortion on phone calls at certain volumes. I noticed it with certain pitches in peoples voices it would cause a vibration in the ear speaker and some distortion in the sound. Kind of like the speaker is being over driven or has too much power going to it. It usually goes away if I turn the volume almost all the way down, but this is obviously not a practical option since I'm not always making phone calls in a dead silent room. The speaker phone works fine. This only happens when I'm using the earpiece. Is this normal? Is it related to the camera autofocus sensor rattle? Are the sound vibrations from a person's voice enough to set off the rattle? It's really annoying as I tend to make phone calls a lot and I don't like using speaker phone or a headset. Does anyone else have this problem?
From what I can tell, it happened and was normal in the S4. (http://forum.xda-developers.com/showthread.php?t=2280930).
Please help. Im deciding if i need to return it.
..
fffft said:
It's too bad that you didn't describe it in more detail.. i.e. give us steps to replicate it. A recording of the distortion would have been helpful too. I haven't noticed what you describe but it sounds like the gain or auto gain is too high and your earpiece speaker is being overdriven.
There is a gain setting in the service mode menu but first you need to distinguish an app issue or possibly damaged speaker before messing around in the hidden settings. See if you can find an audio app that will give you a wider adjustment range for your system volume and gain.,
.
.
Click to expand...
Click to collapse
Thank you for the reply.
If you go into the service menu, the go into the low frequency test. At 100hz and 200 hz there is a little bit of buzz in the headset reciever unless you really push it against your face (which i assume kind of tightens the spaces in the plastic and prevents whatever vibration in the speaker is occuring).
Hmm.. the vibration is akin to as if you were speaking into some cellophane wrap; like some film (maybe for waterproofing) is covering the speaker.
Oh. It's also worth noting that I cannot replicate the issue on Skype or Viber. Those sound crystal clear.
Bump. Anyone?
Hi,
I've been experiencing an issue since I've had this phone for a little more than 1 month.
If I'm wearing my wired earphones (don't have Bluetooth ones) and the phone makes use of the network (as when a video or a song starts to load) I can hear a buzzing distortion sound in the background as long as the download is in progress. In fact, I have a network speed meter on the status bar and when I'm not doing anything the phone jumps from OB/s to 1kB/s every once in a while (which is normal) also resulting in an audible hissing sound in the background through the earphones.
What the hell is this? It's pretty annoying especially when a YouTube video begins to play.
Nothing here
Yup, pretty normal when poor isolation of RF is done hardware-wise. There is probably nothing software that can be done about it except for better frequency filtering on hardware/driver side.
You pretty much have to live with it; back when I still had my Axon I barely noticed it and only when I was lying in bed right before sleep.
I doubt @front firing speakers does not have it on his phone.
You have to be in a very silent environment and set the volume to really really low to be able to notice it.
The Nexus 9 tablet is also very prominent in this regard, or the Nexus 7 2013 speakers (not headphones). A variety of devices have this issue.
What you could do to confirm it is hook up and oscilloscope to your 3.5mm input jack, play a video at exactly ZERO volume and look at the frequency of the signal you got there